Audiometer



July 28, 1970' E.IP.I MERRILL AUDIOME'I'ER 3 Sheets-Sheet 1 Filed May 8, 1968 INVENTOR EVERETT P. MERRILL ATTORNEY y 1970 E. P. MERRILL 3,522,377

AUDIOMETER Filed May 8, 1968 3 Sheets-Sheet 2 FIG. 4

INVENTOR EVERETT P. MERRILL jam/"e141 M ATTORNEY July 28, 1970 v E. R. MERRILL AUDIOMETER 3 Sheets-Sheet 3 Filed May 8, 1968 INVENTOR EVERETT F? MERRILL PIC 16 ATTORNEY United States Patent 3,522,377 AUDIOMETER Everett P. Merrill, 3626 Grafton, Dallas, Tex.

Filed May 8, 1968, Ser. No. 727,422 Int. Cl. H01r 29/00; G01k /00 U.S. Cl. 179--1 9 Claims ABSTRACT OF THE DISCLOSURE This invention pertains to audiometers, more particularly to audiometers having a single control unit for selecting the frequency and intensity of the tone produced by the audiometer, and even more particularly, to an audiometer whose frequency and intensity control unit has a marker included therewith for indicating hearing loss information on a record card.

Within the field of medical diagnosis, and particularly within the field of hearing diagnosis, there is a continuing demand for audiometer apparatus which is relatively inexpensive to manufacture, and simple to operate. Two types of apparatus are generally employed within this field. First, there is the complex and sophisticated equipment which can ordinarily be operated by a trained physician or technician and which gives thorough and exhaustive information about the patients hearing ability. Second, there is the relatively simple apparatus which may be operated by an unskilled operator or even the patient himself, the information received from this apparatus giving an initial indication as to whether further testing and/or exhaustive treatment is required.

It is therefore a primary object of the invention to provide an improved a udiometer which may be operated by an unskilled operator or the patient himself.

It is a further object of the invention to provide an audiometer having a minimum number of controls, and which can be simply and inexpensively manufactured.

It is a still further object of the invention to provide an audiometer which produces a written record of the hearing status of an individual, this record being effected by the patient in response to audio signals received from the apparatus.

In accordance with these and other objects, the audiometer of the present invention includes a housing having an opening therein adapted to receive a card for recording hearing loss information thereupon. A pair of terminal boards or plates having unique conductive patterns upon their respective faces and a plurality of slots formed therein are mounted within the housing so that each of the plurality of slots in the boards are mutually vertically aligned with one another. A single control unit which alters both the frequency and the intensity of the tone produced by the internal circuitry of the audiometer is adapted to slide within corresponding sets of slots and make electrical contact between terminal portions of the unique conductive pattern on the parallel mounted boards or plates. Such an arrangement eliminates the requirement of existing audiometers presently on the market to have lot:

individual knobs or dials for adjusting the frequency and the intensity of the tone.

In accordance with another feature of the invention, the combination frequency and intensity selector unit has a retractable marker associated with it, this marker adapted to contact and mark the record card and record the hearing loss information in response to the tones heard by the patient being tested. In accordance with another feature, the entire apparatus may be turned on in response to the record card being inserted into the housing.

Additional features of the invention, as well as its operation and advantages, are included in the following detailed description taken in conjunction with the accompanying drawings, wherein:

FIG. 1 is a pictorial view, partially in phantom, of the preferred embodiment of the invention;

FIG. 2 is a partially exploded view of the circuit boards or plates illustrating the unique conductive patterns thereupon;

FIG. 3 is a side view of the apparatus depicted in FIG. 1;

FIG. 4 is a detailed drawing of the single frequency and intensity selector unit illustrating its cooperative relationship with the circuit boards or plates shown in FIG. 2;

FIG. 5 is a record card having hearing loss diagnostic information recorded thereupon; and

FIG. 6 is a schematic of one form of circuitry which may be employed in the apparatus of the invention.

Referring now to the drawings, the audiometer of the present invention is designated generally by the reference numeral 10, and includes a housing comprising topand bottom portions 11 and 12, respectively, backing 13 and front piece 14 (as illustrated in FIGS. 1 and 3). A plurality of slots 23 are located within the top cover 11, and an opening or aperture 15 is provided within the front face 14 of the housing, this opening adapted to receive a record card 16. This card 16 may be inserted through the opening 15 and into the interior of the housing by the individual whose hearing is to be tested, all as to be subsequently described, a ledge or shelf 17 supporting this card, as illustrated in FIG. 3.

The housing may be fabricated of various commercially available materials, including a wide range of plastics, and may have its base portion 12, rear wall 13, and adjoining side walls formed as a single molded piece, with the cover 11 and front portion 14 removably mounted therewith.

Within the housing of the audiometer 10 are included a pair of terminal boards or plates 20 and 21, switch means 65, and associated circuitry (illustrated in FIG. 3 as contained within subhousing 81).

A plurality of slots 24 is provided within terminal board or sheet 20, and a plurality of slots 25 is similarly provided within sheet 21. The sheets 20- and 2-1 are mounted in parallel within the housing of the apparatus 10, the slots 24 and 25 being in mutual vertical alignment and registry with corresponding ones of each other, as well as with slots 23 of cover portion 11, as illustrated in FIG. 1. The boards 20 and 21 may be secured to the housing by conventional screws, for example, indicated generally at 22; and spacers 26 may be utilized to assure parallel mounting and mutual alignment of all corresponding slots, as described above.

The terminal plate or board 20 comprises an electrically insulating substrate 28 with the desired electrically conductive pattern formed thereupon (depicted in FIG. 2 as the shaded portion). Accordingly, a plurality of metallic strips f f overlie the insulating substrate 28 on the top surface 20a adjacent each of the slots 24. These strips are electrically continuous for their entire length, as shown in FIG. 2. Another layer of metal forms a common conductive area 30 which has leg portions also immediately adjacent the slots 24, this conductive region 30 being electrically isolated from the terminal strips f f by the slots 24 and/ or portions of the insulating substrate 28. Identical conductive patterns are formed on the. underside 20b of the board 20 providing strips f '-f and common conductive area 30, as well as on the underside 21b of the board 21, providing conductive strips f and common conductive area 30".

The terminal plate or board 21 comprises an electrically insulating substrate 29 with another desired electrically conductive pattern formed thereupon. Accordingly, a plurality of contact or conductive terminal areas L -L overlie the side 21a, and are disposed adjacent each of the slots 25, each of the areas L -L being electrically isolated from one another by the substrate portion 29. A common conductive area 40 is isolated from the pads L L and has leg portions immediately adjacent the slots 25 and spaced from the pads L L by these slots.

The terminal boards or plates 20 and 21 may be formed by selectively applying the desired conductive pattern to a ceramic substrate, or they may be of the copper-clad circuit board variety, wherein the overlying bonded copper layer is selectively etched or removed to provide the unique conductive pattern. Various types of metal and insulating combinations may be utilized consistent with the ultimate construction design.

As illustrated in the circuit schematic of FIG. 6, the conductive patterns on each side of the boards 20 and 21 provide terminal connections which are coupled to the internal circuitry of the apparatus Within the subhousing 81. Accordingly, terminals h-f and f are respectively coupled to a bank 87 of capacitors and a bank 88 of resistors, these two banks jointly serving as R-C networks for varying the frequency of a tone heard in the audio transducer or earphone 70.

The terminal areas L -L on the side 21a are coupled to a ladder network 89 of resistors which provides an attenuator circuit for varying the intensity of the tone heard within the headset 70. To minimize space and circuitry, each of the terminals L of FIG. 2 may be shorted together by wires, for example, so that only one bank 89 of resistors need be employed. Similarly, all L s, L s, L s, etc., are shorted.

A bank 90 of variable value resistors is connected with terminals f 'f on side b and provides calibration for the earphone 70 so that the audio output at each frequency at the zero reference level (terminal L for example) corresponds to the normal threshold of hearing at that frequency.

The remaining circuitry includes a source 82 of DC voltage, a switch 65, transistor amplifier 84, an oscillator provided by transistor 83 and associated resistors and capacitors, and an oscilaltor transformer 85 from which different frequencies may be derived and coupled to the earphone 70.

Each set of mutually aligned slots (for example the set provided by 23a, 24a, and 25a) thus corresponds to a specified frequency value established by the internal circuitry of FIG. 6. As five sets of mutually aligned slots are illustrated in FIGS. 1 and 2, they may respectively represents 250, 500, 1000, 2000, and 4000 cycles per second, or any other desired values.

On the other hand, each of the terminal portions L L L etc., adjacent the slots 25 corresponds to a different intensity level of the tone as established by the attenuator portion of the internal circuitry. Thus, L may correspond to a zero db reference level, L to 10 db, L to 20 db L to 70 db, for example.

Referring to FIGS. 1, 3, and 4, a unit 50 having electrical contact projections 60, 61, 62 and 63 integrally connected therewith is adapted to slide simultaneously within one of the sets of slots 23, 24, and 25. Accordingly, when the unit 50 is inserted into mutually aligned slots 23a, 24a, and 25a, contact projection shorts terminal strip f;., to conductive area 30 on side 20, and contact projections 61 and 63 simultaneously short terminal strips f and f to conductive areas 30' and 30" respectively. At the same time, and in accordance with the operation of the invention, the unit 50 may be moved along the slot 25a (and also consequently the slots 24a and 23a) to enable the contact projection 62 to short common terminal 40 to any one of the terminal pads L -L adjacent slot 25a. The width of the projection 62 should assure that only one of the terminal areas L L is shorted to the area 40 at one time. In this manner, a single control unit 50 may be utilized to change the frequency and intensity of the tone heard in the earphone 70.

A retractable marker point 53 coupled to plunger 51 is also included with unit 50, and is adapted to make contact with record card 16 in accordance with the subsequently described use of the apparatus. A guide block 54 on the inside of the front face 14 engages with the notch 52 located in the unit 50 as this unit is moved from one set of slots to another.

The operation of the audiometer 10 is now described. The earphone is initially placed over the right or left ear of the subject whose hearing is to be tested, the record card 16 is then inserted into the opening 15 for a sufficient distance to close the spring switch 65 against the terminal 80, thus turning on the apparatus.

The switch control unit 50 is then inserted into one of the sets of slots and moved along and parallel to the slots, thereby causing a corresponding increase in intensity of the tone at that particular frequency. When the individual first hears the signal tone in the earphone, he depresses the plunger 51 causing the marker 53 to place a dot on the record card 16. The control unit 50 is then moved to the next set of slots (representing a different frequency) and the procedure is repeated. When the test is completed, the card 16 is removed from the unit 10, and an evaluation made of the test results. As observed in FIG. 5, each of the five dots imprinted on the card 16 represents the level or intensity of a tone at the specific frequency when the tone first becomes audible to the patient being tested. From this information, the need for further testing and/or hearing assistance is determined.

Various modifications of the disclosed embodiment may be employed utilizing the single intensity and frequency control unit in conjunction with the terminal board layouts. For example, the specific internal circuitry of FIG. 6 is merely illustrative of one type network that may be employed with the novel switching arrangement of the invention. Various other modifications of the disclosed embodiment, as well as further embodiments may become obvious to one ordinarily skilled in the art without departing from the true spirit and scope of the invention, as defined by the appended claims.

What is claimed is:

1. An audiometer, comprising:

(a) a housing having an opening therein adapted to receive a card for recording hearing loss information thereupon,

(b) a pair of parallel plates within said housing, each of said plates having a plurality of slots formed therein, the plurality of slots in one of the said plates being mutually aligned and in registry with corresponding slots in the other of said plates,

(c) a set of electrically isolated contact portions adjacent each of the plurality of slots in said one plate, ((1) an electrically continuous contact portions, adjacent each of the correspondingly aligned slots in said other plate,

(e) means including a retractable marker for contacting said card said means being simultaneously slidable within a pair of correspondingly aligned slots in said pair of plates, said slidable means having first and second contact projections, said first projection contacting respective ones of said set of electrically isolated contact portions while said second contact projection simultaneously contacts an electrically continuous contact portion,

(f) attenuator circuit means coupled to each set of electrically isolated contact portions for varying the intensity of a tone, and electric circuit means coupled to the continuous contact portions for varying the frequency of said tone, whereby the movement of said slidable means along said corresponding aligned slots of said plates changes the intensity of said tone while the frequency of said tone remains constant, and

(g) acoustical transducer means electrically coupled to said attenuator and frequency varying circuit.

2. An audiorneter for determining the hearing loss of a subject being tested, said audiometer comprising:

(a) a housing having a base portion thereof,

(b) a pair of insulating boards mounted in parallel with said base portion, each of said pair of boards having two major faces thereof and a plurality of slots therein, the slots in one board being mutually aligned and in registration with corresponding slots in said other board,

(0) a conductive pattern upon at least one major face of each of said boards providing terminal connections,

((1) frequency varying circuit means electrically connected with the terminal connections on one of said boards,

(e) intensity varying circuit means electrically connected with the terminal connections on the other of said boards,

(f) an earphone electrically coupled to said frequency varying and intensity varying circuit means, and

(g) a switch control unit slidably mounted within a respective pair of said mutually aligned slots of said boards, said control unit having a pair of contact projections which respectively simultaneously contact select terminal connections of said one board and select terminal connections of the said other board.

3. The audiorneter as described in claim 2 wherein said housing has a cover with slots therein mutually aligned with said plurality of mutually aligned slots of each of said boards, said switch control unit extending through one of the mutually aligned slots in said cover.

4. The audiorneter as described in claim 2 wherein said housing has an opening therein to receive a card for recording hearing loss information thereupon, and said switch control unit includes a retractable marker for marking said card, said card being supported by said portion.

5. The audiometer as described in claim 4 including a switch for turning on the audiorneter, said switch being activated by the insertion of said card into said opening.

6. The audiorneter as described in claim 2 wherein the conductive pattern providing the terminal connections on the said major face of said one board comprises elongated electrically continuous conductive strips adjacent respective ones of the slots in said one board, and the conductive pattern providing terminal connections on the said major face of the other said board comprises a plurality of sets of electrically isolated contact areas, each set being respectively adjacent each of the slots in said other board.

7. The audiorneter as described in claim 6 wherein a conductive pattern is respectively On each of the remaining major faces of the said pair of boards and is identical to the conductive pattern on the said major face of said one board, and another pair of contact projections of said switch control unit simultaneously contact portions of the conductive pattern on each of said remaining major faces.

8. The audiorneter as described in claim 7 wherein the conductive pattern on one of said remaining major faces is electrically connected with calibration circuitry for said earphone.

9. An audiorneter for determining the hearing loss of an individual, comprising a first circuit board having a plurality of first conductive terminals associated therewith; a second circuit board having a plurality of second conductive terminals associated therewith; an acoustical transducer; first circuit means for providing variable frequencies of a tone sensed by said acoustical transducer, said first circuit means electrically connected with said plurality of first conductive terminals of said first circuit board; second circuit means for varying the intensity of said tone, said second circuit means electrically connected with said plurality of second conductive terminals of said second circuit board; and a single control unit having contact portions which respectively simultaneously contact a select one of said first conductive terminals while slidably contacting select ones of said plurality of second conductive terminals, thereby to change the intensity of said tone for each frequency thereof.

References Cited UNITED STATES PATENTS Re. 21,735 3/1941 Huth et al.

2,257,262 9/1941 Koren. 2,781,416 2/1957 Brogan. 2,802,053 8/ 1957 Wiese.

KATHLEEN H. CLAFFY, Primary Examiner C. W. IIRAUCH, Assistant Examiner US. Cl. X.R. 33918 

